North London Derby: Are Spurs and Mauricio Pochettino reaching the end?

Tottenham's manager deviated from a career spent tracing the foothills of Sir Alex Ferguson's legacy. The sunny disposition that many had come to expect from him was abandoned in favour of following a different kind of predecessor in the Manchester United hot seat.

Pochettino's sullen demeanour during Spurs' pre-season campaign, which saw him tell reporters his job title should be changed from manager to head coach, was the first real sign of a change of tact.

Official confirmation, however, came in the form of a public declarations of love for the 'sarcastic' ex-Red Devils boss rather than its most successful one.

Exactly 12 months ago, he was the Portuguese's antithesis. All roads seemed to lead to Old Trafford for the Argentine after a comprehensive 3-0 win over a lacklustre United. Pochettino was hotly tipped to replace an increasingly beleaguered Mourinho.

Last weekend’s first defeat of the Premier League season against Newcastle United, however, underlined how quickly the mood has changed.

Largely, Pochettino has learned to roll with the punches during his five years at White Hart Lane. Take last season, for example. Spurs’ prolonged stay at Wembley coupled with a lack of new signings could have been disastrous. Spurs, instead, rallied to an improbable Champions League final appearance.

But the picture appears to have shifted. Rumours of his imminent departure, though greatly exaggerated, have resurfaced again ahead of Sunday's North London derby with Arsenal. Another loss to their arch-rivals would add further fuel to the fire of uncertainty.

Pochettino now seemingly prefers to choose politics over philosophy – a staple of Mourinho's notorious endgame strategy. Omitting both Christian Eriksen and Jan Vertonghen from the starting line-up against Newcastle appeared to be power moves which backfired spectacularly.

Undoubtedly the ambiguity over the Denmark international's future ahead of the European transfer window's closure has impacted on Spurs' fortunes, contrary to Pochettino's claims. He insisted that Eriksen's absence had no bearing on the outcome in the loss to the Magpies.

Eriksen has been a key figure in Pochettino's success at Tottenham (Photo by Robbie Jay Barratt - AMA/Getty Images)

Hopes that a forward line of Harry Kane, Lucas Moura and Son-Heung Min would recapture the form which propelled them to a 5-0 hammering of Bournemouth on Boxing Day last year overlooked the importance of Eriksen's creativity, arguably the driving force for the win.

The former Ajax playmaker has invariably become the lightning rod for Spurs' malaise. Until his fate is determined, one way or another, Pochettino's disenchantment will remain. Even if he does stay, there are no guarantees that his manager will have another change of heart.

Not so long ago, both player and coach seemed destined for Real Madrid. Florentino Perez had other ideas, in re-appointing Zinedine Zidane and sanctioning Eden Hazard's signing. Eriksen's hopes of a move to Barcelona appear equally unlikely in the current climate.

Eriksen's exit would be disastrous in the short-term for Tottenham but it could steer Pochettino back on-course with Ferguson's teachings. The United legend held a long-standing view that each successful team has a maximum lifespan of four years before enforcing change.

The core of Tottenham’s squad, of which Eriksen is a vital part, has remained consistent throughout Pochettino's five-year tenure. Perhaps the end of a cycle is approaching.

There is no shortage of potential candidates to make way. Vertonghen heads up a list of 30-somethings that also includes compatriot Toby Alderweireld and, from next summer, Danny Rose. That poses its own dilemmas in overhauling what has been a largely solid defence.

A hallmark of Mourinho's latter managerial career became his inability to rebuild teams for the long-term. Success was often swift but so, too, was the subsequent decline in fortunes. Pochettino could be forgiven for thinking that the Portuguese coach was onto something.

That lack of strategic planning threatens to undermine Pep Guardiola's assertion earlier this month that Tottenham are currently 'the second best team in Europe'. Last season's Champions League finalists could have conceivably faced tougher groups than one of Bayern Munich, Red Star Belgrade and Olympiacos but are by no means guaranteed to qualify.

On the home front, Pochettino also has to make up lost ground. He heads to the Emirates Stadium this weekend with a point to prove to himself as well as others. Tottenham have not have not won on their Premier League travels since January 20th while he has never tasted a domestic victory in their neighbours' backyard.